Civil Engineering Reference
In-Depth Information
Table 6.3
Progress of hydration and strength development of alinite cement and its
constituents.
w/s
1d
3d
7d
28 d
Degree of hyration (%)
Alinite
0.25
53
54
62
10
43
51
79
>95
Calcium aluminochloride
0.25
34
48
55
10
45
>90
Belite
10
35
47
64
82
Alinite cement
10
35
47
64
82
Compressive strength (MPa)
Alinite
0.25
-
42.3
58.9
65.4
Calcium aluminochloride
0.36
-
48.2
53.2
64.8
Alinite cement
0.25
-
49.5
57.1
69.3
Source:
Ji
et al.
(1997)
1 a C-S-H phase similar to that formed in the hydration of Portland cement and
portlandite (Ca(OH)
2
), both produced in the hydration of the alinite phase and belite.
2 Friedel's salt (C
3
A.CaCl
2
.10H
2
O) or—more likely—a product in which part of the
CaCl
2
is substituted by Ca(OH)
2
or CaCO
3
. This phase is formed in the hydration of
calcium aluminochloride and also the ferrite phases. In the latter case Al
3+
may be
partly substituted by Fe
3+
.
3 If calcium sulfate is interground with alinite clinker, an AFt phase may be also formed.
It converts to monosulfate in the latter course of hydration.
4 Other phases that may be present in small amounts include CAH
10
and C
3
AH
6
.
A significant part of the chlorine originally present in the alinite clinker becomes bound
within the C
3
A.CaCl
2
.10H
2
O phase in the course of hydration. It has also been reported
(Ji
et al.,
1997) that the formed C-S-H phase may accommodate up to 3.5% Cl, probably
by adsorption. Significant amounts of Cl
−
, however, enter the liquid phase. Cl
−
concentrations of around 1 mg/ml have been reported for hydration times between 1 and
28 days (Ji
et al.,
1997). At the same time the aluminate concentration stayed at around
16-18 µg/ml and the CaO concentration at around 2
µ
g/ml. The following chlorine
concentrations in the pore solution were reported by Kostogloudis
et al.
(1998):
